Thread Content
Author/Source: http://www.chemall.com.cn/ Date: 2009-4-7 -------------------------------------------------------------------------------- Experts believe that the technologies for producing methanol and dimethyl ether from coal are more mature than those used for producing oil from coal. On March 30, it was reported that Sinopec, which has long been interested in coal-to-oil projects, has purchased foreign technologies and equipment for coal-to-oil production at the pilot scale, taking the first step in its roadmap to enter this industry. This indicates that the coal-to-oil industry, which was once surrounded by controversy, is showing a clear trend of accelerating its development. In response, many experts who have always been skeptical about the industrialization of coal-to-oil production once again warn that there are numerous problems associated with this approach, and caution is still needed when pursuing its industrialization. The issue of energy consumption remains unresolved. For coal-to-oil production to achieve industrial development, the first challenge to overcome is the high energy consumption and low energy efficiency resulting from technical bottlenecks. Coal-to-oil production requires a large amount of water resources, which undoubtedly poses inherent constraints on provinces with abundant coal but limited water supplies such as Shanxi and Inner Mongolia. Moreover, the current level of technology means that at least 4 tons of coal are required to produce one ton of \"oil\"; if production is scaled up, it is essentially replacing one scarce resource with another. Jin Yong, a professor at Tsinghua University and an academician of the Chinese Academy of Engineering, told China Energy News that although Inner Mongolia Yitai Group uses its own technology for coal-to-oil production, 4 tons of coal are still required to produce one ton of oil. The F-T synthetic oil technology introduced by Sinopec from the United States, although already widely used abroad, still fails to address the issue of high energy consumption. **Zhou Dadi, former director of the Energy Research Institute of the National Development and Reform Commission, also pointed out that China’s own coal resources are facing a threat of shortage. Moreover, multiple conversions of energy inevitably result in greater losses at intermediate stages; therefore, from the perspective of maximizing energy utilization, this is not cost-effective, and it does not fall within the scope of what a resource-conserving society should do. Furthermore, coal-to-oil production results in massive carbon dioxide emissions. Based on 3.5 tons of carbon dioxide produced per ton of coal, emissions will increase by 700 million to 900 million tons per year. This astonishing figure is in clear contradiction to China’s current international commitments to \"reduce greenhouse gas emissions and address global climate change.\" Alcohols and ethers derived from coal are a better option; in fact, many experts are seeking better alternative methods and technologies to address the problems associated with coal-based oil production. Professor Jin Yong has long been engaged in research on coal chemical technology. He stated that, when seeking alternatives to scarce resources and energy, it is necessary to adopt a concept of functional substitution rather than sticking to the replacement of identical products; the goal is to achieve resource and energy conservation as well as reduced pollution. The purpose of converting coal into oil is to provide liquid fuel for cars, ships, and airplanes, and the fuel does not have to be gasoline or diesel. In response, Jin Yong made a comparison: in the process of direct coal liquefaction for oil production, the output is mainly low-quality diesel, and the energy consumption is 4–4.5 tons of standard coal ； Indirect coal liquefaction for oil production yields low-quality gasoline and diesel, with an energy consumption of 5–5.5 tons of standard coal ； Dimethyl ether is synthesized as a substitute for diesel; compared to diesel, it offers an engine efficiency improvement of 10%–15%, its exhaust emissions meet Euro III standards, and its energy consumption is 2.2–2.5 tons of standard coal ； In methanol synthesis, the product can be used either mixed with gasoline or on its own; the energy consumption is 1.8–2.2 tons of standard coal, indicating that the energy consumption levels of various approaches vary significantly. Theoretically, the energy utilization efficiency ratios for coal-based methanol, dimethyl ether, and diesel are 1:0.714:0.438 respectively; in other words, using methanol or dimethyl ether as substitutes for oil can save about half of the coal resources required for coal-based oil production. Moreover, the technologies for producing methanol and dimethyl ether from coal are currently more mature in China compared to those for producing oil from coal. It is advisable to build technical reserves; whether it comes to coal-to-oil or coal-to-alcohols and ethers, the attitude toward these technologies is becoming increasingly cautious. **Zhang Guobao, head of the Energy Bureau, once stated clearly: \"The enthusiasm of local governments and enterprises to develop the coal chemical industry should be guided positively, in order to prevent blind development and excessive investment.\" "Industry policies related to coal chemical industry, the establishment of industry standards, and the standards for blending methanol and dimethyl ether into gasoline **will not be introduced in the short term. "Some domestic companies, under the pretext of pursuing energy strategy goals, are pushing for coal-to-oil projects to be established throughout the country, which will entail significant policy risks. If it is truly for **energy strategy considerations, then coal-based clean energy should be regarded as a technical reserve; in the event of an energy crisis, it would be the right approach to carry out small-scale coal-to-oil production in order to supply energy. "Professor Jin Yong said.